Pallets, and especially wooden pallets are an essential component in the shipping and handling of commercial goods. The demand for pallets continues to increase each year, with the result that improvements in the apparatus and methods used in their construction are desirable. Pallets are constructed by assembling a number of wood, plastic or metal members to produce a frame structure with internal support members and top and bottom surfaces upon which freight is placed and the pallet rests. While pallets can be constructed by hand, the development of machine methods of pallet construction permits an individual operator to build pallets more accurately, rapidly, and safely.
Machines for building pallets are known in the art, as disclosed for example in U.S. Pat. No. 5,249,352 to Landers and Canadian Patent Number 2,446,055 to the present inventor Tremblay. Once the pallet is finished it is moved off the pallet making machine, and commonly onto to a pallet stacker which stacks the pallets for convenient storage.
Typically such a pallet stacker provides a vertical frame that defines a pallet opening between right and left vertical frame members. A bottom or floor of the pallet opening comprises a lift mechanism. Typically the distance between the vertical frame members can be adjusted to suit pallets of varying widths. The operator slides the pallet in a horizontal orientation between the vertical frame members and onto the lift mechanism. The lift mechanism then moves the pallet upward between the vertical frame members. Typically catches are positioned on the vertical frame members such that same are pushed upward by the upward moving pallet, and once the pallet moves up past the catches, the catches fall back down under the pallet. The lift mechanism then moves downward but the pallet rests on the catches above the opening and the lift mechanism moves down to a position under the pallet opening, ready to receive another pallet and repeat the process.
In such pallet stackers, the lift mechanism typically operates automatically through a cycle of raising the pallet and then dropping to receive another pallet automatically in response to the operator activating a switch. Thus the lift mechanism can move relatively slowly while the operator is making the next pallet, and still be ready to receive the next pallet when it is finished. When a desired number of pallets have been stacked, the pallet stacker can in some cases provide a mechanism that will allow the stack of pallets to be rolled out of the stacker to make room for a new stack, or the stack can be removed with a forklift or the like.
U.S. Pat. No. 5,355,575 to Self discloses a pallet moving device for moving a finished pallet off a slant table upon which it is made, and onto a pallet stacker. Such slant tables provide a convenient operator position for pallet assembly and nailing, and are commonly used as also shown in Canadian Patent Number 2,446,055 to Tremblay and in U.S. Pat. No. 4,077,106 to Lichtenstein et al. The Self device moves the finished pallet upward and rearward off the slant table using two arms.
U.S. Pat. No. 4,492,016 to Smets et al. discloses a pivoting assembly table which can be slanted at varying degrees for assembly, and a pair of runways with rollers mounted thereon beneath the table. The mechanism allows the finished pallet to drop onto the runways and roll away to a stacker or other location.
It is also common in less automated machines for the operator to simply manually lift the pallet off the assembly table and slide into the pallet opening on a pallet stacker located in front of the assembly table and beside the location where the operator would ordinarily stand while using the machine. Where the assembly table is in the common slanted orientation, the operator will normally pull the top of the pallet toward him while the bottom of the pallet rests on the front bottom edge of the table, pivoting the pallet up and over such that the pallet surface that was resting on the assembly table moves to a horizontal position on top of the pallet. The operator will then lift the pallet, align it with the pallet opening in the pallet stacker, and then slide it into the pallet opening.